Synergistically UV-photoprotecting benzotriazole-substituted silicon/cinnamic acid compositions

ABSTRACT

Topically applicable cosmetic/dermatological compositions suited for improvedly UV-photoprotecting human skin and/or hair against the deleterious effects of ultraviolet irradiation, advantageously oil-in-water emulsions, contain SPF-synergistically enhancing amounts of (a) at least one UV-screening benzotriazole-substituted silicon compound and (b) at least one UV-screening cinnamic acid derivative, formulated into (c) a topically applicable, cosmetically/dermatologically acceptable vehicle, diluent or carrier therefor.

CROSS-REFERENCE TO PRIORITY/PCT APPLICATIONS

[0001] This application claims priority under 35 U.S.C. § 119 ofFR-99/08568, filed Jul. 2, 1999, and is a continuation of itscorresponding PCT/FR-00/01696, filed Jun. 20, 2000 (WO-01/01946), bothhereby expressly incorporated by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Technical Field of the Invention

[0003] The present invention relates to novel cosmetic/dermatologicalcompositions for topical application, for the ultraviolet(UV)-photoprotection of human skin and/or hair, comprising (a) at leastone silicon compound containing a benzotriazole substituent as a firstUV-screening agent, and (b) as a second UV-screening agent, at least onecinnamic acid derivative.

[0004] The present invention more especially relates to the aforesaidUV-photoprotecting compositions wherein said first and said secondsunscreens are present in such respective amounts as to providesynergistically enhanced activity with respect to the sun protectionfactors (SPFs) imparted thereto.

[0005] 2. Description of the Prior Art

[0006] It is known to this art that light radiation with wavelengths offrom 280 nm to 400 nm promotes tanning of the human epidermis, and thatlight rays with wavelengths of from 280 to 320 nm, known as UV-Bradiation, cause skin burns and erythema which may be harmful to thedevelopment of a natural tan; this UV-B radiation should thus bescreened from the skin.

[0007] It is also known that UV-A rays, with wavelengths of from 320 to400 nm, which promote tanning of the skin, are liable to induce anadverse change therein, especially in the case of sensitive skin or ofskin which is continually exposed to solar radiation. UV-A rays cause,in particular, a loss of elasticity of the skin and the appearance ofwrinkles, leading to premature skin aging. UV-A radiation promotestriggering of the erythemal reaction or amplifies this reaction incertain individuals and may even be the source of phototoxic orphotoallergic reactions. It is thus desirable to also screen out UV-Aradiation.

[0008] A wide variety of cosmetic compositions for the sunblockprotection (UV-A and/or UV-B) of the skin have to date been proposed.

[0009] These antisun/sunscreen compositions are quite often in the formof an emulsion of oil-in-water type (namely, a cosmetically acceptablesupport comprising a continuous aqueous dispersing phase and adiscontinuous oily dispersed phase) which contains, in variousconcentrations, one or more conventional lipophilic and/or hydrophilicorganic screening agents which are capable of selectively absorbingharmful UV radiation. These screening agents (and the amounts thereof)are selected as a function of the desired sun protection factor ((SPF)which is expressed mathematically by the ratio of the irradiation timenecessary to attain the erythema-forming threshold with the UV screeningagent to the time required to attain the erythema-forming thresholdwithout UV screening agent.

[0010] Cosmetic UV-screening agents comprising lipophilic siliconecompounds substituted by a benzotriazole functional group and which havegood screening properties both in the UV-A radiation range and in theUV-B radiation range are also known to the prior art. They are describedin EP-A-0,392,883; EP-A-0,660,701; EP-A-0,708,108; EP-A-0,711,778;EP-A-711,779.

[0011] EP-A-0,742,003 and EP-A-0,860,165 describe combining thesesilicone screening agents bearing benzotriazole functional groups withspecific water-soluble screening agents containing a sulfonic function,namely, benzene-1,4-bis(3-methylidene-10-camphorsulfonic acid) or2-phenylbenzinidazole-5-sulfonic acid and salts thereof, in order toimpart a synergistic effect with respect to the sun protection factorsthereof. These synergistic screening systems require at least oneaqueous phase for dissolving the water-soluble screening agent and afatty phase for dissolving the silicone screening agent; thissubstantially reduces the options for the formulation thereof.

[0012] EP-A-0,835,094 describes combining these silicone screeningagents bearing a benzotriazole functional group with two otherlipophilic screening agents, namely, a dibenzoylmethane compound and analkyl P,p-diphenylacrylate compound. In this instance also, themandatory presence of these three screening agents complicates theirformulation into antisun/sunscreen products.

[0013] UV-screening compositions based on silicon derivatives ofbenzotriazole in dissolved form containing at least one cinnamicderivative in an amount which is sufficient by itself to dissolve saidsilicone screening agent are described in French patent application No.98/12042. This '042 application, in particular, describes a formulationexample in the form of an oil-in-water emulsion containing 0.5% byweight of stearic acid, 2.5% by weight of stearyl alcohol, 2% by weightof polydimethylsiloxane, 0.22% of acrylic thickening polymer, 0.72% byweight of triethanolamine, 8% by weight of moisturizer, 5% by weight ofdrometrizole trisiloxane and 10% by weight of 2-ethylhexylp-methoxycinnamate. It does not describe any synergistic effect on theprotection factors with the benzotriazole-substituted silicon compound.

SUMMARY OF THE INVENTION

[0014] It has now surprisingly and unexpectedly been determined thatimmixture, in proportions within well-defined limits, of a UV-screeningagent of the benzotriazole/silicon derivative type and of a UV-screeningagent of the cinnamic acid derivative type elicits a marked synergisticeffect on the sun protection factors provided thereby. Such admixtureprovides antisun/sunscreen compositions whose sun protection factors aremarkedly improved, and in all instances considerably superior to thosewhich can be obtained with either one of the screening agents formulatedalone.

[0015] Too, the specific combinatory admixture of UV-screening agents inaccordance with the invention is readily formulated into a very widerange of cosmetic/dermatological supports, i.e., vehicles, diluents orcarriers therefor.

[0016] Briefly, the present invention features novelcosmetic/dermatological compositions, in particular antisun/sunscreencompositions comprising, formulated into cosmetically/dermatologicallyacceptable supports therefor:

[0017] (i) at least one benzotriazole-substituted silicon compound, as afirst UV-screening agent; and

[0018] (ii) at least one cinnamic acid derivative, as a secondUV-screening agent, with the proviso that said first and secondUV-screening agents are present in the subject compositions inproportions which provide synergistically enhanced activity on the sunprotection factors imparted. The subject compositions are other thanoil-in-water emulsions containing 0.5% by weight of stearic acid, 2.5%by weight of stearyl alcohol, 2% by weight of polydimethylsiloxane,0.22% of acrylic thickening polymer, 0.72% by weight of triethanolamine,8% by weight of moisturizer, 5% by weight of drometrizole trisiloxaneand 10% by weight of 2-ethylhexyl p-methoxycinnamate.

[0019] The present invention also features a regime/regimen forprotecting the skin and/or the hair against the deleterious effects ofultraviolet radiation, in particular solar radiation.

[0020] This invention also features formulating a cinnamic derivativeinto cosmetic/dermatological compositions suited for photoprotecting theskin and/or the hair against ultraviolet radiation, in particular solarradiation, and comprising at least one UV-screening agent of thebenzotriazole/silicon type, to elicit a synergistic effect on the sunprotection factors imparted thereto.

DETAILED DESCRIPTION OF BEST MODE AND SPECIFIC/PREFERRED EMBODIMENTS OFTHE INVENTION

[0021] More particularly according to the present invention, the siliconcompounds substituted by a benzotriazole functional group are preferablysilanes or siloxanes containing a benzotriazole function, comprising atleast one structural unit of formula (1) below:

O_((3-a)/2)Si(R₇)_(a)—G  (1)

[0022] in which R₇ is an optionally halogenated C₁-C₁₀ alkyl radical, aphenyl radical, or a trimethylsilyloxy radical; a is an integer rangingfrom 0 to 3, inclusive; and G is a monovalent radical directly bonded toa silicon atom and having the structural formula (2) below:

[0023] in which the radicals Y, which may be identical or different, areeach a C₁-C₈ alkyl radical, a halogen atom, or a C₁-C₄ alkoxy radical,with the proviso that, in the latter instance, two adjacent radicals Yon the same aromatic ring can together form an alkylidenedioxy radicalwherein the alkylidene moiety has 1 or 2 carbon atoms; X is 0 or NH; Zis hydrogen or a C₁-C₄ alkyl radical; n is an integer ranging from 0 to3, inclusive; m is 0 or 1; and p is an integer ranging from 1 to 10,inclusive.

[0024] These compounds are described in particular, in EP-A-0,392,882;EP-A-0,660,701; EP-A-0,708,108; EP-A-0,711,778; EP-A-711,779.

[0025] The silicon derivatives according to the present inventionpreferably belong to the general family of benzotriazole silicones whichis described, in particular, in EP-A-0,660,701.

[0026] One family of benzotriazole silicones which is particularlypreferred according to the present invention is that which includes thecompounds corresponding to structural formula (5) or (6) below:

[0027] in which the radicals R₇, which may be identical or different,are each a C₁-C₁₀ alkyl, phenyl, 3,3,3-trifluoropropyl ortrimethylsilyloxy radical, at least 80% by number of the radicals R₇being methyl radicals; the radicals D, which may be identical ordifferent, are each a radical R₇ or a radical G; r is an integer rangingfrom 0 to 50, inclusive, and s is an integer ranging from 0 to 20,inclusive, with the proviso that if s=0, at least one of the tworadicals D is a radical G; u is an integer ranging from 1 to 6,inclusive, and t is an integer ranging from 0 to 10, inclusive, with theproviso that t+u is equal to or greater than 3; and the radical G hasthe structural formula (2) above.

[0028] As will be seen from formula (2) given above, bonding of thedivalent radical —(X)_(m)—(CH₂)_(p)—CH(Z)—CH₂— to the benzotriazolefunction, which thus ensures attachment of said benzotriazole functiondirectly to a silicon atom of the silicone chain, may be at any and allof the available positions of the two aromatic rings of thebenzotriazole:

[0029] Preferably, this bonding is at position 3, 4, 5 (aromatic ringbearing the hydroxyl function) or 4′ (benzene ring adjacent to thetriazole ring), and even more preferably is at position 3, 4 or 5. In amore preferred embodiment of the invention, the bonding is at position3.

[0030] Similarly, attachment of the substituent unit or units Y may beat any and all of the other positions available in the benzotriazole.However, preferably, this bonding is at position 3, 4, 4′, 5 and/or 6.In a more preferred embodiment of the invention, bonding of the radicalY is at position 5. In formulae (5) and (6) above, the alkyl radicalsmay be linear or branched and are selected, in particular, from amongmethyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl,n-amyl, isoamyl, neopentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl andtert-octyl radicals. The preferred alkyl radicals R₇ according to theinvention are methyl, ethyl, propyl, n-butyl, n-octyl and 2-ethylhexylradicals. Even more preferably, the radicals R₇ are all methyl radicals.

[0031] Among the compounds of formula (5) or (6) above, preferred arethose corresponding to formula (5), namely, diorganosiloxanes containinga short linear chain.

[0032] Among the compounds of formula (5) above, preferred are those forwhich the radicals D are both radicals R₇.

[0033] Among the linear diorganosiloxanes according to the presentinvention, more particularly preferred are random derivatives orwell-defined block derivatives having at least one, and even morepreferably all, of the following characteristics:

[0034] D is a radical R₇;

[0035] R₇ is an alkyl radical and even more preferably is methyl;

[0036] r ranges from 0 to 15, inclusive;

[0037] s ranges from 1 to 10, inclusive;

[0038] n is other than zero and preferably is equal to 1, and Y is thena methyl, tert-butyl or C₁-C₄ alkoxy radical;

[0039] Z is hydrogen or methyl;

[0040] m=0 or [m=1 and X=0]; and

[0041] p is equal to 1.

[0042] One family of benzotriazole silicones which is particularlysuitable according to this invention is that having the structuralformula (7) below:

[0043] in which 0≦r≦10; 1≦s≦10; and E is the divalent radical:

[0044] In a particularly preferred embodiment of this invention, thebenzotriazole silicone is the compound Drometrizole Trisiloxane (CTFAname) corresponding to the following structural formula:

[0045] Processes which are suitable for the preparation of the compoundsof formulae (1), (5), (6) and (7) above are described, in particular, inU.S. Pat. Nos. 3,220,972, 3,697,473, 4,340,709, 4,316,033 and 4,328,346and also in EP-A-0,392,883 and EP-A-0,742,003.

[0046] The silicon compound substituted by a benzotriazole function isadvantageously present in the compositions according to the invention incontents of from 0.1% to 20% by weight, preferably from 0.2% to 15% byweight, still relative to the total weight of the composition.

[0047] Exemplary cinnamic acid derivatives according to the presentinvention include isopentyl 4-methoxycinnamate, 2-ethylhexyl4-methoxycinnamate, methyl diisopropylcinnamate, isoamyl4-methoxycinnamate and diethanolamine 4-methoxycinnamate.

[0048] Among the cinnamic acid derivatives indicated above, mostparticularly preferred is 2-ethylhexyl p-methoxycinnamate which ismarketed under the trademark “Parsol MCX” by Givaudan; this UV-screeningagent has the following structural formula:

[0049] The cinnamic acid derivative(s) of the invention is(are)advantageously present at contents ranging from 0.1% to 20% by weightand preferably from 0.2% to 15% by weight relative to the total weightof the composition.

[0050] As indicated above, one essential functional characteristic ofthe present invention is that the two types of sunscreen should both bepresent in the final composition in a respective proportion such that asynergistic effect on the protection factor imparted by the resultingcombination is obtained in an appreciable, substantial and significantmanner.

[0051] In addition, and generally, it should be appreciated that theconcentrations and ratios of benzotriazole silicon derivative and ofcinnamic acid derivative are selected such that the sun protectionfactor of the final composition is preferably at least 2.

[0052] The weight ratio of the cinnamic derivative to the benzotriazolesilicon derivative will preferably range from 0.5/6.5 to 6.75/0.25.

[0053] The sunscreen cosmetic/dematological compositions according tothe invention can of course contain one or more additional hydrophilicor lipophilic sunscreens that are active in the UV-A and/or UV-B range(absorbers) other than the two particular screening agents indicatedabove. These additional screening agents are advantageously selectedfrom among salicylic derivatives, camphor derivatives; triazinederivatives such as those described in EP-863,145, EP-517,104,EP-570,838, EP-796,851, EP-775,698 and EP-878,469; benzophenonederivatives; dibenzoylmethane derivatives; β,β-diphenylacrylatederivatives; benzimidazole derivatives; p-aminobenzoic acid derivatives;hydrocarbon-based bis(benzotriazolyl-phenol) derivatives such as thosedescribed in GB-A-2,303,549, DE-19726184 and EP-A-893,119; compoundscomprising at least two benzazolyl groups such as those described inEP-A-0,669,323; and screening polymers and screening silicones such asthose described in WO-93/04665.

[0054] Exemplary such additional sunscreens that are active in the UV-Aand/or UV-B range include:

[0055] p-aminobenzoic acid,

[0056] oxyethylenated (25 mol) p-aminobenzoate,

[0057] 2-ethylhexyl p-dimethylaminobenzoate,

[0058] N-oxypropylenated ethyl p-aminobenzoate,

[0059] glyceryl p-aminobenzoate,

[0060] homomenthyl salicylate,

[0061] 2-ethylhexyl salicylate,

[0062] triethanolamine salicylate,

[0063] 4-isopropylbenzyl salicylate,

[0064] 4-tert-butyl-4 ′-methoxydibenzoylmethane,

[0065] 4-isopropyldibenzoylmethane,

[0066] menthyl anthranilate,

[0067] 2-ethylhexyl 2-cyano-3,3′-diphenylacrylate,

[0068] ethyl 2-cyano-3,3′-diphenylacrylate,

[0069] 2-phenylbenzimidazole-5-sulfonic acid and salts thereof,

[0070] 3-(4′-trimethylammonium)benzylidenebornan-2-one methyl sulfate,

[0071] 2-hydroxy-4-methoxybenzophenone,

[0072] 2-hydroxy-4-methoxybenzophenone 5-sulfonate,

[0073] 2,4-dihydroxybenzophenone,

[0074] 2,2′,4,4′-tetrahydroxybenzophenone,

[0075] 2,2′-dihydroxy-4,4′-dimethoxybenzophenone,

[0076] 2-hydroxy-4-n-octoxybenzophenone,

[0077] 2-hydroxy-4-methoxy-4′-methylbenzophenone,

[0078] α-(2-oxoborn-3-ylidene)tolyl-4-sulfonic acid and salts thereof,

[0079] 3-(4′-sulfo)benzylidenebornan-2-one and salts thereof,

[0080] 3-(4′-methylbenzylidene)-d,1-camphor,

[0081] 3-benzylidene-d,1-camphor,

[0082] benzene-1,4-bis(3-methylidene-10-camphorsulfonic acid) and saltsthereof, urocanic acid,

[0083] 2,4,6-tris[p-(2′-ethylhexyl-1′-oxycarbonyl)anilino]-1,3,5-triazine,

[0084] 2-[(p-(tert-butylamido)anilino]-4,6-bis[(p-(2′-ethylhexyl-1′-oxycarbonyl)anilino]-1,3,5-triazine,

[0085]2,4-bis{[4-(2-ethyl-hexyloxy)]-2-hydroxy]phenyl}-6-(4-methoxyphenyl)-1,3,5-triazine,

[0086] N-(2 and 4)-[(2-oxoborn-3-ylidene)methyl]benzyl]acrylamidepolymer,

[0087] 4,4-bis-benzimidazolyl-phenylene-3,3′,5,5′-tetrasulfonic acid andsalts thereof,

[0088] 2,2′-methylenebis[6-(2H-benzotriazole-2-yl)-4(1,1,3,3-tetramethylbutyl)phenol],polyorganosiloxanes substituted by a malonate functional group.

[0089] The compositions according to the invention may also containagents for the sunless or artificial tanning and/or browning of the skin(self-tanning agents) such as, for example, dihydroxyacetone (DHA).

[0090] The cosmetic/dematological compositions of this invention mayalso contain pigments or nanopigments (average size of the primaryparticles: generally ranging from 5 nm to 100 nm, preferably from 10 nmto 50 nm) of coated or uncoated metal oxides, such as, for example,nanopigments of titanium dioxide (amorphous or crystallized in rutileand/or anatase state), of iron oxide, of zinc oxide, of zirconium oxideor of cerium oxide which are all UV-photoprotective agents that are wellknown per se. Standard coating agents are, moreover, alumina and/oraluminum stearate. Such coated or uncoated metal oxide nanopigments aredescribed, in particular, in EP-A-0,518,772 and EP-A-0,518,773.

[0091] The compositions of the present invention may also comprisestandard cosmetic additives and adjuvants selected, in particular, fromamong fatty substances, organic solvents, thickeners, softeners,antioxidants, opacifiers, stabilizers, emollients, hydroxy acids,anti-foaming agents, moisturizers, vitamins, fragrances, preservatives,surfactants, fillers, sequestering agents, propellants, basifying oracidifying agents, dyes, colorants or any other ingredientconventionally employed in cosmetics, in particular for the formulationof antisun/sunscreen compositions as emulsions.

[0092] The fatty substances may comprise an oil or a wax or mixturesthereof, and they also comprise fatty acids, fatty alcohols and fattyacid esters. Exemplary oils include animal, plant, mineral or syntheticoils and, in particular, liquid petrolatum, liquid paraffin, volatile ornon-volatile silicone oils, isoparaffins, poly-α-olefins, fluoro oilsand perfluoro oils. Similarly, exemplary waxes include animal, fossil,plant, mineral or synthetic waxes that are known per se.

[0093] Exemplary organic solvents include the lower alcohols andpolyols.

[0094] The thickeners are advantageously selected from among crosslinkedacrylic acid homopolymers and modified or unmodified guar gums andcellulose gums such as hydroxypropylated guar gum,methylhydroxyethylcellulose, hydroxypropylmethylcellulose, orhydroxyethylcellulose.

[0095] One skilled in this art will of course take care to select theoptional complementary compound or compounds indicated above and/or theamounts thereof such that the advantageous properties, especially theenhanced sunblock effect, intrinsically associated with the binarycombination in accordance with the invention are not, or aresubstantially not, adversely affected by the addition or additionsenvisaged.

[0096] The compositions of the invention may be formulated according totechniques which are well known to this art, in particular those suitedfor the preparation of emulsions of oil-in-water or water-in-oil type,or, alternatively, anhydrous compositions.

[0097] The subject compositions may be, in particular, in simple orcomplex emulsion form (O/W, W/O, O/W/O or W/O/W), such as a cream, amilk, a lotion, an ointment, a gel or a cream-gel, or in the form of apowder, a solid composition or soft pastes and may optionally bepackaged as an aerosol and may be in the form of a foam, mousse, orspray.

[0098] When the composition is an emulsion, the aqueous phase thereofmay comprise a nonionic vesicular dispersion prepared according to knowntechniques (Bangham, Standish and Watkins, J. Mol. Biol., 13, 238(1965), FR-2,315,991 and FR-2,416,008).

[0099] The cosmetic compositions of the invention are well suited ascompositions for photoprotecting the human epidermis or the hair againstthe deleterious effects of ultraviolet radiation, as anantisun/sunscreen composition or as a makeup product.

[0100] When the cosmetic/dermatological compositions according to theinvention are formulated for protecting the human epidermis against UVrays or as an antisun/sunscreen composition, they may be in the form ofa suspension or dispersion in solvents or in fatty substances, in theform of a nonionic vesicular dispersion, or, alternatively, in the formof an emulsion, preferably of oil-in-water type, such as a cream or amilk, or in the form of an ointment, a gel, a cream-gel, a stick, softpastes, an aerosol foam or a spray.

[0101] When the cosmetic/dermatological compositions according to theinvention are formulated to protect the hair, they may be in the form ofa shampoo, a lotion, a gel, an emulsion or a nonionic vesiculardispersion and may constitute, for example, a rinse-out composition tobe applied before or after shampooing, before or after dyeing orbleaching, before, during or after permanent-waving or straightening ofthe hair, a styling or treating lotion or gel, a blow-drying orhair-setting lotion or gel, or a composition for permanent-waving,straightening, dyeing or bleaching the hair.

[0102] When the subject compositions are formulated as makeup productsfor the eyelashes, the eyebrows or the skin, such as an epidermaltreatment cream, a foundation, a lipstick, an eyeshadow, a blusher, amascara or an eyeliner, they may be in solid or pasty, anhydrous oraqueous form, for example oil-in-water or water-in-oil emulsions,nonionic vesicular dispersions or suspensions.

[0103] For example, for the antisun/sunscreen formulations in accordancewith the invention which have a support of oil-in-water emulsion type,the aqueous phase (in particular comprising the hydrophilic screeningagents) generally constitutes from 50% to 95% by weight, preferably from70% to 90% by weight, relative to the total weight of the overallformulation, the oily phase (in particular comprising the lipophilicscreening agents) from 5% to 50% by weight, preferably from 10% to 30%by weight, relative to the total weight of the overall formulation, andthe (co)emulsifying agent(s) from 0.5% to 20% by weight, preferably from2% to 10% by weight, relative to the total weight of the overallformulation.

[0104] One particular embodiment of the invention is a care and/ormakeup stick for the lips comprising at least one of the compositionsdescribed above.

[0105] As above indicated, the present invention also features acosmetic treatment regime/regimen for the skin or the hair to protectsame against the damaging effects of UV rays, comprising topicallyapplying an effective amount of a subject cosmetic composition onto theskin or the hair.

[0106] In order to further illustrate the present invention and theadvantages thereof, the following specific examples are given, it beingunderstood that same are intended only as illustrative and in nowiselimitative.

EXAMPLES 1 to 12

[0107] % by Common support: care stick for the lips weightMicrocrystalline wax 5.00 Glyceryl trihydroxystearate 5.00 Ozokerite3.40 Polyglycerolated beeswax 2.10 Acetylated lanolin 19.45 Lanolin oil19.10 Avocado oil 18.99 Butene/isobutene copolymer 14.34 Castor oil 4.81Ascorbyl palmitate 0.50 Mixture of tocopherols in soybean oil (50/50)0.31 2-ethylhexyl para-methoxycinnamate (Parsol MCX) X (*) Drometrizoletrisiloxane Y With X + Y = 7% by weight

[0108] Drometrizole trisiloxane has the structural formula:

[0109] For each of the Examples 1 to 12, the sun protection factor (SPF)associated therewith was determined. This was determined via the invitro method disclosed by B.L. Diffey et al. in J. Soc. Cosmet. Chem.,40 127-133 (1989). The measurements were carried out using an SPF 290 Smodel UV-visible spectrophotometer from Optometrics equipped with anintegration sphere and a xenon lamp.

[0110] Each cosmetic formulation was applied onto a Transpore adhesivetape from 3M adhered to a quartz slide, in the form of a homogeneous anduniform deposit at a rate of 2 mg/cm².

[0111] The compositions of the various formulations studied and theresults obtained in terms of average sun protection factor (average offive tests) are reported in the Table below: TABLE Screening Ex. Ex. Ex.Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. agent 1 2 3 4 5 6 7 8 9 10 11 12 % X7 6.75 6.50 6.00 5.00 4.00 3.00 2.00 1.00 0.50 0.25 0 % Y 0 0.25 0.501.00 2.00 3.00 4.00 5.00 6.00 6.50 6.75 7 Average 9.8 ± 10.6 ± 13.0 ±13.4 ± 12.3 ± 12.4 ± 12.5 ± 11.4 ± 12.5 ± 11.8 ± 13.0 ± 8.9 ± SPF ±standard 0.3 0.7 0.5 0.7 2.1 2.1 1.8 1.4 2.0 1.7 1.7 0.9 deviation

[0112] These results evidence that a significant synergistic effect wasprovided by combining the cinnamic derivative and the benzotriazolesilicon derivative in weight ratios of the cinnamic derivative to thebenzotriazole silicon derivative ranging from 0.50/6.50 to 6.75/0.25.

[0113] While the invention has been described in terms of variousspecific and preferred embodiments, the skilled artisan will appreciatethat various modifications, substitutions, omissions, and changes may bemade without departing from the spirit thereof. Accordingly, it isintended that the scope of the present invention be limited solely bythe scope of the following claims, including equivalents thereof.

What is claimed is:
 1. A topically applicable cosmetic/dermatologicalcomposition suited for improvedly UV-photoprotecting human skin and/orhair against the deleterious effects of ultraviolet irradiation,comprising SPF-synergistically enhancing amounts of (a) at least oneUV-screening benzotriazole-substituted silicon compound and (b) at leastone UV-screening cinnamic acid derivative, formulated into (c) atopically applicable, cosmetically/dermatologically acceptable vehicle,diluent or carrier therefor.
 2. The cosmetic/dermatologicalUV-photoprotecting composition as defined by claim 1 , said at least oneUV-screening benzotriazole-substituted silicon compound (a) comprising asilane and/or polyorganosiloxane containing at least one structural unithaving the formula (1): O_((3-a)/2)Si(R₇)_(a)—G  (1) in which R₇ is anoptionally halogenated C₁-C₁₀ alkyl radical, a phenyl radical, or atrimethylsilyloxy radical; a is an integer ranging from 0 to 3,inclusive; and G is a monovalent radical directly bonded to a siliconatom and having the structural formula (2):

in which the radicals Y, which may be identical or different, are each aC₁-C₈ alkyl radical, a halogen atom, or a C₁-C₄ alkoxy radical, with theproviso that, in the latter instance, two adjacent radicals Y on thesame aromatic ring can together form an alkylidenedioxy radical whereinthe alkylidene moiety has 1 or 2 carbon atoms; X is 0 or NH; Z ishydrogen or a C₁-C₄ alkyl radical; n is an integer ranging from 0 to 3,inclusive; m is 0 or 1; and p is an integer ranging from 1 to 10,inclusive.
 3. The cosmetic/dermatological UV-photoprotecting compositionas defined by claim 2 , said at least one UV-screeningbenzotriazole-substituted silicon compound (a) having either of thestructural formulae (5) and (6):

in which the radicals R₇, which may be identical or different, are eacha C₁-C₁₀ alkyl, phenyl, 3,3,3-trifluoropropyl, or trimethylsilyloxyradical, at least 80% by number of the radicals R₇ being methylradicals; the radicals D, which may be identical or different, are eacha radical R₇ or a radical G; r is an integer ranging from 0 to 50,inclusive, and s is an integer ranging from 0 to 20, inclusive, with theproviso that if s=0, at least one of the two radicals D is a radical G;U is an integer ranging from 1 to 6, inclusive, and t is an integerranging from 0 to 10, inclusive, with the proviso that t+u is equal toor greater than 3; and the radical G has the structural formula (2). 4.The cosmetic/dermatological UV-photoprotecting composition as defined byclaim 1 , said at least one UV-screening benzotriazole-substitutedsilicon compound (a) having the structural formula (7):

in which 0≦r≦10; 1≦s≦10; and E is the divalent radical:


5. The cosmetic/dermatological UV-photoprotecting composition as definedby claim 1 , said at least one UV-screening benzotriazole-substitutedsilicon compound (a) comprising drometrizole trisiloxane having thestructural formula:


6. The cosmetic/dermatological UV-photoprotecting composition as definedby claim 1 , comprising from 0.1% to 20% by weight of said at least oneUV-screening benzotriazole-substituted silicon compound (a).
 7. Thecosmetic/dermatological UV-photoprotecting composition as defined byclaim 1 , comprising from 0.2% to 15% by weight of said at least oneUV-screening benzotriazole-substituted silicon compound (a).
 8. Thecosmetic/dermatological UV-photoprotecting composition as defined byclaim 1 , said at least one UV-screening cinnamic acid derivative (b)comprising isopentyl 4-methoxycinnamate, 2-ethylhexyl4-methoxycinnamate, methyl diisopropylcinnamate, isoamyl4-methoxycinnamate and/or diethanolamine 4-methoxycinnamate.
 9. Thecosmetic/dermatological UV-photoprotecting composition as defined byclaim 8 , said at least one UV-screening cinnamic acid derivative (b)comprising 2-ethylhexyl 4-methoxycinnamate having the structuralformula:


10. The cosmetic/dermatological UV-photoprotecting composition asdefined by claim 1 , comprising from 0.1% to 20% by weight of said atleast one UV-screening cinnamic acid derivative (b).
 11. Thecosmetic/dermatological UV-photoprotecting composition as defined byclaim 1 , comprising from 0.2% to 15% by weight of said at least oneUV-screening cinnamic acid derivative (b).
 12. Thecosmetic/dermatological UV-photoprotecting composition as defined byclaim 1 , having an SPF of at least
 2. 13. The cosmetic/dermatologicalUV-photoprotecting composition as defined by claim 1 , the ratio byweight of said at least one cinnamic acid derivative (b) to said atleast one benzotriazole-substituted silicon compound (a) ranging from0.5/6.5 to 6.75/0.25.
 14. The cosmetic/dermatological UV-photoprotectingcomposition as defined by claim 1 , further comprising at least oneadditional hydrophilic or lipophilic organic UV-A and/or UV-B sunscreen.15. The cosmetic/dermatological UV-photoprotecting composition asdefined by claim 14 , further comprising at least one salicylicsunscreen, camphor sunscreen, benzophenone sunscreen, dibenzoylmethanesunscreen, triazine sunscreen, β,β-diphenylacrylate sunscreen,p-aminobenzoic acid sunscreen, bis(benzotriazolylphenol) sunscreen,sunscreen comprising at least two benzazolyl functional groups,sunscreen polymer and/or sunscreen silicone other than onebenzotriazole-substituted.
 16. The cosmetic/dermatologicalUV-photoprotecting composition as defined by claim 1 , furthercomprising a UV-photoprotecting effective amount of particulates of atleast one inorganic pigment or nanopigment.
 17. Thecosmetic/dermatological UV-photoprotecting composition as defined byclaim 16 , said at least one pigment or nanopigment comprising titaniumdioxide, zinc oxide, iron oxide, zirconium oxide, cerium oxide, ormixture thereof.
 18. The cosmetic/dermatological UV-photoprotectingcomposition as defined by claim 1 , further comprising at least oneactive agent for the artificial tanning and/or browning of human skin.19. The cosmetic/dermatological UV-photoprotecting composition asdefined by claim 1 , further comprising at least one cosmeticallyacceptable adjuvant or additive.
 20. The cosmetic/dermatologicalUV-photoprotecting composition as defined by claim 19 , said at leastone adjuvant or additive comprising a fat, organic solvent, thickeningagent, softener, antioxidant, opacifying agent, stabilizing agent,emollient, hydroxy acid, anti-foaming agent, hydrating agent, vitamin,fragrance, preservative, surfactant, filler, sequestering agent,polymer, propellant, basifying or acidifying agent, dye, colorant, ormixture thereof.
 21. The cosmetic/dermatological UV-photoprotectingcomposition as defined by claim 1 , formulated as an emulsion, cream,gel, milk, cream-gel, powder, solid, stick, suspension, mousse, foam,lotion, spray, dispersion, or ointment.
 22. The cosmetic/dermatologicalUV-photoprotecting composition as defined by claim 21 , formulated as anoil-in-water emulsion.
 23. The cosmetic/dermatologicalUV-photoprotecting composition as defined by claim 1 , comprising amakeup product.
 24. The cosmetic/dermatological UV-photoprotectingcomposition as defined by claim 23 , comprising an epidermal treatmentcream, a foundation, a lipstick, an eyeshadow, a blusher, a mascara, oran eyeliner.
 25. The cosmetic/dermatological UV-photoprotectingcomposition as defined by claim 21 , comprising a shampoo, a hairlacquer, a rinse, a hair styling/treating lotion or gel, or a hairreshaping, straightening, dyeing or bleaching formulation.
 26. Aregime/regimen for photoprotecting human skin and/or hair against thedeleterious effects of UV-irradiation, comprising topically applyingthereon a cosmetic/dermatological composition comprisingSPF-synergistically enhancing amounts of (a) at least one UV-screeningbenzotriazole-substituted silicon compound and (b) at least oneUV-screening cinnamic acid derivative, formulated into (c) a topicallyapplicable, cosmetically/dermatologically acceptable vehicle, diluent orcarrier therefor.
 27. The cosmetic/dermatological UV-photoprotectingcomposition as defined by claim 1 , other than an oil-in-water emulsioncontaining 0.5% by weight of stearic acid, 2.5% by weight of stearylalcohol, 2% by weight of polydimethylsiloxane, 0.22% of acrylicthickening polymer, 0.72% by weight of triethanolamine, 8% by weight ofmoisturizer, 5% by weight of drometrizole trisiloxane and 10% by weightof 2-ethylhexyl p-methoxycinnamate.